Gunfire noise can produce up to 180 decibels in milliseconds a fact sometimes overlooked by recreational hunters. Noises above 140 dB are usually considered to be highly dangerous to human ears, and repeated exposure to noise at this level virtually guarantees hearing loss over time.

Dr. Patrick Brookhouser, director of the Boys Town National Research Hospital, studied kids who go out hunting with their dads. He says, "We found, for example, the average right-handed individual fires with their ear sort of cocked over to one side so that the ear that actually gets the exposure is the left ear. And we've noticed in these kids, for whatever reason that the right ear was getting more exposure. And it turns out, I think they were standing next to their father."

Gunshots are classified as impulse noises, which are very, very short in duration. In the case of some impulse noises like gunshots, however, their extremely intense sounds can cause an immediate drop in hearing. One of the warning signs of this kind of damage is a continuing ringing in the ear(s) long after the noise has stopped.

Keith Wilson served in the military more than 20 years ago. Following stints on the military firing range he suffered from a buzzing sound in his ears for months. Today he has trouble picking out some of the higher-frequency speech sounds, so he's experimenting with some of the new digital hearing aids -- at $2500 a pop.

Compared to 20 or 30 years ago hearing loss has been greatly reduced in the military. Since roughly the time when Wilson left the military, they have been engaged in efforts to prevent hearing loss. Although these efforts have greatly reduced hearing in the military, it remains one of the most expensive health care compensation costs in the armed forces.

  Video 19: Hearing damage in the military

  Video 20: Hunting and hearing damage